The Experts below are selected from a list of 84006 Experts worldwide ranked by ideXlab platform
Mohamed-slim Alouini - One of the best experts on this subject based on the ideXlab platform.
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On the average outage rate and average outage duration of wireless communication systems with multiple cochannel interferers
IEEE Transactions on Wireless Communications, 2004Co-Authors: Lin Yang, Mohamed-slim AlouiniAbstract:This paper studies the average outage rate [or average level crossing rate (LCR)] and average outage duration (AOD) of wireless communication systems subject to cochannel interference. In particular, it presents closed-form expressions for the LCR and AOD when a minimum desired signal Power Requirement is specified for satisfactory reception. The results are quite general and account for systems operating over independent identically distributed Rician and/or Nakagami fading environments. When applicable, these new expressions are compared to those previously reported in the literature dealing with the LCR and AOD of 1) interference-limited systems when both the desired and interfering signals are subject to Rayleigh type of fading and 2) Power-limited systems operating over Rician or Nakagami fading channels. Corresponding numerical examples that illustrate applications of the results are also provided and discussed. These results show that specifying a certain minimum desired signal Power Requirement induces a floor on the AOD. They also show that the AOD is essentially affected by the the maximum Doppler frequencies (or equivalently the speed) of the desired users.
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average outage duration of multiuser wireless communication systems with a minimum signal Power Requirement
Vehicular Technology Conference, 2002Co-Authors: Lin Yang, Mohamed-slim AlouiniAbstract:This paper deals with the average outage duration (AOD) of wireless communication systems subject to cochannel interference. In particular, it presents closed-form expressions for the AOD when a minimum desired signal Power Requirement is specified for satisfactory reception. The results are quite general and account for systems operating over Rician and/or Nakagami fading environments. When applicable, these new expressions are compared to those previously reported in the literature dealing with the AOD of (i) interference-limited systems when both the desired and interfering signals are subject to Rayleigh type of fading and (ii) Power-limited systems operating over Rician or Nakagami fading channels. Corresponding numerical examples that illustrate applications of the results are also provided and discussed. These results show that specifying a certain minimum desired signal Power Requirement induces a floor on the AOD. They also show that the AOD is essentially affected by the the maximum Doppler frequencies (or equivalently the speed) of the desired users.
Changsoo Kim - One of the best experts on this subject based on the ideXlab platform.
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energy management strategies of a fuel cell battery hybrid system using fuzzy logics
Journal of Power Sources, 2005Co-Authors: Kwiseong Jeong, Wonyong Lee, Changsoo KimAbstract:Abstract Hybrid Power systems with fuel cells and batteries have the great potential to improve the operation efficiency and dynamic response. A proper load management strategy is important for both better system efficiency and endurance of hybrid systems. In this paper, a fuzzy logic algorithm has been used to determine the fuel cell output Power depending on the external Power Requirement and the battery state of charge (SoC). If the Power Requirement of the hybrid system is low and the SoC is low, then the greater part of the fuel cell Power is used to charge the battery pack. If the Power Requirement is relatively high and the SoC is also high, then the fuel cell and the battery are concurrently used to supply the required Power. These if–then operation rules are implemented by fuzzy logic for the energy management of the hybrid system. The strategy is evaluated using simulation and experimental results. The results show that the operation efficiency of hybrid system was improved and the battery SoC maintained at reasonable level. The control scheme can be used to optimize the operational efficiency of hybrid Power generation system.
Lin Yang - One of the best experts on this subject based on the ideXlab platform.
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On the average outage rate and average outage duration of wireless communication systems with multiple cochannel interferers
IEEE Transactions on Wireless Communications, 2004Co-Authors: Lin Yang, Mohamed-slim AlouiniAbstract:This paper studies the average outage rate [or average level crossing rate (LCR)] and average outage duration (AOD) of wireless communication systems subject to cochannel interference. In particular, it presents closed-form expressions for the LCR and AOD when a minimum desired signal Power Requirement is specified for satisfactory reception. The results are quite general and account for systems operating over independent identically distributed Rician and/or Nakagami fading environments. When applicable, these new expressions are compared to those previously reported in the literature dealing with the LCR and AOD of 1) interference-limited systems when both the desired and interfering signals are subject to Rayleigh type of fading and 2) Power-limited systems operating over Rician or Nakagami fading channels. Corresponding numerical examples that illustrate applications of the results are also provided and discussed. These results show that specifying a certain minimum desired signal Power Requirement induces a floor on the AOD. They also show that the AOD is essentially affected by the the maximum Doppler frequencies (or equivalently the speed) of the desired users.
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average outage duration of multiuser wireless communication systems with a minimum signal Power Requirement
Vehicular Technology Conference, 2002Co-Authors: Lin Yang, Mohamed-slim AlouiniAbstract:This paper deals with the average outage duration (AOD) of wireless communication systems subject to cochannel interference. In particular, it presents closed-form expressions for the AOD when a minimum desired signal Power Requirement is specified for satisfactory reception. The results are quite general and account for systems operating over Rician and/or Nakagami fading environments. When applicable, these new expressions are compared to those previously reported in the literature dealing with the AOD of (i) interference-limited systems when both the desired and interfering signals are subject to Rayleigh type of fading and (ii) Power-limited systems operating over Rician or Nakagami fading channels. Corresponding numerical examples that illustrate applications of the results are also provided and discussed. These results show that specifying a certain minimum desired signal Power Requirement induces a floor on the AOD. They also show that the AOD is essentially affected by the the maximum Doppler frequencies (or equivalently the speed) of the desired users.
Prudence W. H. Wong - One of the best experts on this subject based on the ideXlab platform.
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Non-preemptive Scheduling in a Smart Grid Model and Its Implications on Machine Minimization
Algorithmica, 2020Co-Authors: Fu-hong Liu, Hsiang-hsuan Liu, Prudence W. H. WongAbstract:We study a scheduling problem arising in demand response management in smart grid. Consumers send in Power requests with a flexible feasible time interval during which their requests can be served. The grid controller, upon receiving Power requests, schedules each request within the specified interval. The electricity cost is measured by a convex function of the load in each timeslot. The objective is to schedule all requests with the minimum total electricity cost. Previous work has studied cases where jobs have unit Power Requirement and unit duration. We extend the study to arbitrary Power Requirement and duration, which has been shown to be NP-hard. We give the first online algorithm for the general problem and prove that the problem is fixed parameter tractable. We also show that the online algorithm is the best-possible in an asymptotically sense when the objective is to minimize the peak load. In addition, we observe that the classical non-preemptive machine minimization problem is a special case of the smart grid problem with min-peak objective and show that we can achieve the best-possible competitive ratio in an asymptotically sense when solving the non-preemptive machine minimization problem.
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optimal nonpreemptive scheduling in a smart grid model
International Symposium on Algorithms and Computation, 2016Co-Authors: Fu-hong Liu, Hsiang-hsuan Liu, Prudence W. H. WongAbstract:© Fu-Hong Liu, Hsiang-Hsuan Liu, and Prudence W. H. Wong. We study a scheduling problem arising in demand response management in smart grid. Consumers send in Power requests with a flexible feasible time interval during which their requests can be served. The grid controller, upon receiving Power requests, schedules each request within the specified interval. The electricity cost is measured by a convex function of the load in each timeslot. The objective is to schedule all requests with the minimum total electricity cost. Previous work has studied cases where jobs have unit Power Requirement and unit duration. We extend the study to arbitrary Power Requirement and duration, which has been shown to be NP-hard. We give the first online algorithm for the general problem, and prove that the worst case competitive ratio is asymptotically optimal. We also prove that the problem is fixed parameter tractable. Due to space limit, the missing proofs are presented in the full paper.
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Optimal Nonpreemptive Scheduling in a Smart Grid Model
arXiv: Data Structures and Algorithms, 2016Co-Authors: Prudence W. H. WongAbstract:We study a scheduling problem arising in demand response management in smart grid. Consumers send in Power requests with a flexible feasible time interval during which their requests can be served. The grid controller, upon receiving Power requests, schedules each request within the specified interval. The electricity cost is measured by a convex function of the load in each timeslot. The objective is to schedule all requests with the minimum total electricity cost. Previous work has studied cases where jobs have unit Power Requirement and unit duration, and offline setting was considered. We extend the study to arbitrary Power Requirement and duration, which has been shown to be NP-hard. We give the first online algorithm for the problem, and prove the competitive ratio is optimal. We also prove that the problem is fixed parameter tractable.
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Non-preemptive Scheduling in a Smart Grid Model and its Implications on Machine Minimization
arXiv: Data Structures and Algorithms, 2016Co-Authors: Prudence W. H. WongAbstract:We study a scheduling problem arising in demand response management in smart grid. Consumers send in Power requests with a flexible feasible time interval during which their requests can be served. The grid controller, upon receiving Power requests, schedules each request within the specified interval. The electricity cost is measured by a convex function of the load in each timeslot. The objective is to schedule all requests with the minimum total electricity cost. Previous work has studied cases where jobs have unit Power Requirement and unit duration. We extend the study to arbitrary Power Requirement and duration, which has been shown to be NP-hard. We give the first online algorithm for the general problem, and prove that the problem is fixed parameter tractable. We also show that the online algorithm is asymptotically optimal when the objective is to minimize the peak load. In addition, we observe that the classical non-preemptive machine minimization problem is a special case of the smart grid problem with min-peak objective, and show that we can solve the non-preemptive machine minimization problem asymptotically optimally.
Kwiseong Jeong - One of the best experts on this subject based on the ideXlab platform.
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energy management strategies of a fuel cell battery hybrid system using fuzzy logics
Journal of Power Sources, 2005Co-Authors: Kwiseong Jeong, Wonyong Lee, Changsoo KimAbstract:Abstract Hybrid Power systems with fuel cells and batteries have the great potential to improve the operation efficiency and dynamic response. A proper load management strategy is important for both better system efficiency and endurance of hybrid systems. In this paper, a fuzzy logic algorithm has been used to determine the fuel cell output Power depending on the external Power Requirement and the battery state of charge (SoC). If the Power Requirement of the hybrid system is low and the SoC is low, then the greater part of the fuel cell Power is used to charge the battery pack. If the Power Requirement is relatively high and the SoC is also high, then the fuel cell and the battery are concurrently used to supply the required Power. These if–then operation rules are implemented by fuzzy logic for the energy management of the hybrid system. The strategy is evaluated using simulation and experimental results. The results show that the operation efficiency of hybrid system was improved and the battery SoC maintained at reasonable level. The control scheme can be used to optimize the operational efficiency of hybrid Power generation system.
